Thermocouple manometer



' K. KAMBAYASHI vTuvimosoUPLE MANOMETER Filed April 29, 1921 Patented Aug. 26, i924.

NETE@ KAAZUO KAMBAYASHI,

F KUZE-GUN, JAPAN. Y

THERMOCOUBLE MANOMETER.

Application led AprilV 29, 1921. Serial No. 465.552.

To allA whom it may concern.'

. Be it known that I, KAzUo- KAMBAYASHI,

a subject of the Emperor of Japan, residing at No. 47 Uji-cho, Kuze-gun, Kyoto Province, Japan, have invented new and useful Improvements in Thermocouple Manometers (for which I have filed an application in Japan, No. 55,981, April 8, 1920), of which the following is a speciiication.

This invention relates to a thermo-couple manometer consisting of thermo-couples and heating coils sealed in a glass bulb. It has for its object to provide a manometer which may measure a degree of vacuum accurately and easily.

vThe McLeod vacuum gauge without special devices attached, is unreliable on account of the vapour-tension of mercury.

Manometer-s of other types are too complicated or require too much special attention for practical use. According to this invention these disadvantages may be successfully avoided. y

The accompanying drawing shows an example of the present invention. Fig. l is a sectional elevation of a manometer einbodying the principle of the invention, and

Fig. 2 a sectional elevation of a metallic wire of the manometer on a large scale.

In the drawing, 3 and 3 are thermocouples, and 2 and 2 designate heating coils Wound around said couples, which are sealed in glass tubes being held by anchors as clearly shown in Fig. 1. The couples are insulated from the heating coils by means ot' an insulator 4. The temperature surrounding the bulb is maintained constant by means of a suitable apparatus, not shown.

The temperature-rise of a metallic wire' Both bulbs are enclosed in a casing 5 in which a liquid is maintained at a constant temperature. The heating coils 2 and 2' are connected in series, while the thermo-couples 3 and are connected in opposition, the other terminals thereof bein connected to a milivolt-meter 6 as shown in Fig. 1.

By this arrangement, an indication of the milivolt-meter is determined by the temperature diiierence between the junction-points of 3 and 3'; and this temperature difference, in turn, occurs because of the vtemperature difference between the heating coils 2 'and 2.

On account of the' constant degree of vacuum in the bulb l', the temperature difference between the heating coils 2 and 2 depends solely upon the degree of vacuum in the bulb 1, so that the degree of vacuum in the bulb l may be easily determined by the reading of the milivolt-meter.

When the variation of the current through the heating coils and that of the surrounding temperature of thebulbs are small, the change of temperature of the heating coils due to said variations is nearly equal in both bulbs. in view of their series connection. Hence the error due to the variations may be practically neglected.

Then the degree of vacuum in a vessel is to be determined, the vessel is first connected to the mouth of the bulb 1 b a convenient means. Next, the electric circuit to the heating coils is switched'in, and it is regulated to get a constant electric current bv means of a rheostat 7. The current is indicated by an ampere-meter 8. The temperature of the liquid in the casing 5 is maintained constant; it is read by a thermo-meter 9. Thus the reading of the milivolt-meter 6 shows the degree ot vacuum in the bulb 1 as well as the vessel to be determined.

In applying this invention to the manufacturing of an incandescent electric lamp, if the bulb 1 is sealedat a proper degree of vacuum, and a polarized relay, not shown, is connected in place' of theA milivolt-meter 6, the current in the polarized relay changes itS Adirection when the degree of vacuum in the Claimsz- 1. A thermo-couple manometer, comprise ing a pair of bulbs, each provided with a thermo-couple and a heating coil Wound around and insulated from Said couple, one of said bulbsV being sealed and the other open.

2. A. thermo-couple manometer, compris ing a -paii of bulbs, each provided with a thermo-couple and a heating coil Wound around and insulated from said couple, the beating coils of the bulbs being connected iu moi-woe series and the liermo-couples in opposition.

3. A thermo-couple manometer, comprising a pair of bulbs, each provided with a thermo-couple and a heating coil. Wound mound and insulated from said couple, and a easing enclosing said bulbs.

ln testimony whereof l have signed my name to this specification.

MAF/EU@ KANBAYASHL 

